Abstract Objective This study evaluated the clinical effect of violet LED light on in-office bleaching used alone or combined with 37% carbamide peroxide (CP) or 35% hydrogen peroxide (HP). Methodology A total of 100 patients were divided into five groups (n=20): LED, LED/CP, CP, LED/HP and HP. Colorimetric evaluation was performed using a spectrophotometer (ΔE, ΔL, Δa, Δb) and a visual shade guide (ΔSGU). Calcium (Ca)/phosphorous (P) ratio was quantified in the enamel microbiopsies. Measurements were performed at baseline (T 0 ), after bleaching (T B ) and in the 14-day follow-up (T 14 ). At each bleaching session, a visual scale determined the absolute risk (AR) and intensity of tooth sensitivity (TS). Data were evaluated by one-way (ΔE, Δa, ΔL, Δb), two-way repeated measures ANOVA (Ca/P ratio), and Tukey post-hoc tests. ΔSGU and TS were evaluated by Kruskal-Wallis and Mann-Whitney, and AR by Chi-Squared tests (a=5%). Results LED produced the lowest ΔE (p<0.05), but LED/HP promoted greater ΔE, ΔSGU and Δb (T 14 ) than HP (p<0.05). No differences were observed in ΔE and ΔSGU for LED/CP and HP groups (p>0.05). ΔL and Δa were not influenced by LED activation. After bleaching, LED/CP exhibited greater Δb than CP (p>0.05), but no differences were found between these groups at T 14 (p>0.05). LED treatment promoted the lowest risk of TS (16%), while HP promoted the highest (94.4%) (p<0.05). No statistical differences of risk of TS were found for CP (44%), LED/CP (61%) and LED/HP (88%) groups (p>0.05). No differences were found in enamel Ca/P ratio among treatments, regardless of evaluation times. Conclusions Violet LED alone produced the lowest bleaching effect, but enhanced HP bleaching results. Patients treated with LED/CP reached the same efficacy of HP, with reduced risk and intensity of tooth sensitivity and none of the bleaching protocols adversely affected enamel mineral content.

RESUMO Objetivo: Este trabalho analisou a influência da ativação ultrassônica de soluções irrigadoras na penetração do cimento obturador em canais laterais. Métodos: Cinquenta molares superiores (raiz palatina) foram distribuídos aleatoriamente em 5 grupos experimentais (n=10): Grupo 1 (EDTA 17% + agitação manual por 5 minutos), Grupo 2 (EDTA 17% + ativação ultrassônica por 15 segundos), Grupo 3 (NaOCl 1% + ativação ultrassônica por 15 segundos), Grupo 4 (EDTA 17% + ativação ultrassônica por 15 segundos e NaOCl 1% + ativação ultrassônica por 15 segundos) e Grupo 5 (controle negativo). Os canais laterais foram confeccionados nos terços médio e apical. A obturação ocorreu em sessão única e foram realizadas análises radiográficas e microscópicas para avaliar o grau de penetração do cimento obturador. Os dados foram analisados pelos testes de Mann-Whitney e Wilcoxon. Resultados: A análise radiográfica do terço apical e médio mostrou que os Grupos 2 e 4 apresentaram melhor penetração do cimento obturador. Já na análise microscópica, o Grupo 4 apresentou resultados superiores em relação aos demais grupos em ambos os terços. No terço apical, as análises radiográfica e microscópica exibiram diferenças significativas nas comparações entre o Grupo 4 com os Grupos 5 (p = 0,019) e 3 (p = 0,023) e entre o Grupo 5 com os Grupos 2 (p = 0,012), 3 (p = 0,038) e 4 (p = 0,019), respectivamente. Conclusão: Conclui-se que a ativação ultrassônica da solução irrigadora NaOCl 1% + EDTA 17% proporciona maior penetração do cimento endodôntico em canais laterais.

ABSTRACT Objective: This study analyzed the influence of the irrigating solutions ultrasonic activation on the obturator cement penetration into lateral root canals. Methods: Fifty maxillary molars (palatine root) were randomly assigned to 5 experimental groups (Group 1 (EDTA 17% + manual agitation for 5 minutes), Group 2 (EDTA 17% + ultrasonic activation for 15 seconds), Group 3 (NaOCl 1% + Ultrasonic activation for 15 seconds), Group 4 (EDTA 17% + ultrasonic activation for 15 seconds and NaOCl 1% + ultrasonic activation for 15 seconds) and Group 5 (negative control). The lateral root canals were made in the apical and middle third. The obturation occurred in a single session. The radiographic and microscopic analyzes were performed to evaluate the sealant cement penetration degree. Data were analyzed by the Mann-Whitney and Wilcoxon tests. Results: Apical and middle third radiographic analysis showed that Groups 2 and 4 presented better penetration of the sealant cement. In the microscopic analysis, Group 4 presented superior results in relation to the other groups in both thirds. In the apical third, radiographic and microscopic analyzes showed significant differences in the comparisons between Group 4 and Groups 5 (p = 0.019) and 3 (p = 0.023) and between Group 5 and Groups 2 (p = 0.012), 3 (P = 0.038) and 4 (p = 0.019), respectively. Conclusion: It was concluded that the ultrasonic activation of the NaOCl 1% + EDTA 17% irrigation solution provides greater penetration of the endodontic cement in lateral root canals.

Resumo Introdução Métodos de esterilização adotados em Banco de Dentes Humanos podem promover mudanças estruturais no esmalte e na dentina. Assim, o método ideal deve combinar a eficácia antimicrobiana e a preservação das propriedades biomecânicas do substrato. Objetivo Avaliar a morfologia e propriedades físicas do esmalte e dentina dos dentes humanos extraídos, após serem submetidos a diferentes métodos de esterilização. Método Dezesseis terceiros molares extraídos foram seccionados nas seguintes regiões dentárias: mesio-distal, vestibulo-lingual e na junção amelocementária. Quarenta espécimes foram selecionados de acordo com valores de microdureza e rugosidade iniciais, e distribuídos em quatro grupos experimentais (n = 10 / grupo): Grupo 1 = Autoclave 121 °C (30 minutos); Grupo 2 = 2,5% de hipoclorito de sódio (07 dias); Grupo 3 = 5,25% Hipoclorito de sódio (07 dias); Grupo 4 = ácido acético a 30% (7 dias). Após a esterilização, foi avaliada a microdureza, rugosidade e morfologia do esmalte e dentina. Os dados foram analisados pelo teste t pareado, Wilcoxon, Kruskal-Wallis e Análise de Variância. Um nível de significância de 5% foi adotado. Resultado Todos os métodos de esterilização alteraram a microdureza e a rugosidade da dentina (p <0,05). Em relação ao esmalte, a microdureza foi afetada apenas pela Autoclave e pelo tratamento com 2,5% de hipoclorito de sódio (p <0,05). Foi verificada nas micrografias, uma grande abertura dos poros do esmalte e dos túbulos dentinários. Conclusão os métodos de esterilização adotados alteraram a morfologia e / ou propriedades físicas do esmalte e da dentina.

Abstract Introduction Sterilization methods adopted in Human Teeth Bank can promote structural changes in enamel and dentin. Thus, the ideal method should combine the antimicrobial efficacy and preservation of the substrate biomechanical properties. Aim Evaluated the morphology and physical properties of enamel and dentin of extracted human teeth, after being submitted to different sterilization methods. Method Sixteen extracted third molars were sectioned in the following tooth regions: mesio-distal, vestibular-lingual and at the cement enamel junction. Forty specimens were selected according to values of microhardness and roughness initials, and distributed in four experimental groups (n = 10/group): Group 1 = Autoclave 121 °C (30 minutes); Group 2 = 2.5% Sodium hypochlorite (07 days); Group 3 = 5.25% Sodium hypochlorite (07 days); Group 4= 30% Acetic Acid (7 days). After sterilization, the microhardness, roughness and morphology of enamel and dentin were evaluated. Data were analyzed by paired t-test, Wilcoxon, Kruskal-Wallis and Analysis of Variance. A significance level of 5% was adopted. Result All sterilization methods altered the microhardness and roughness of the dentine (p <0.05). Regarding to enamel, the microhardness was affected only by Autoclave and 2.5% Sodium hypochlorite treatment (p <0.05). A large aperture of the enamel pores and dentinal tubules was verified in the micrographs. Conclusion The sterilization methods adopted altered the morphology and/or physical properties of enamel and dentine.

Abstract High concentrations of hydrogen peroxide can cause adverse effects on composition and structure of teeth. However, the addition of calcium and fluoride in bleaching agents may reduce enamel demineralization. Objective: To evaluate chemical changes of sound and demineralized enamels submitted to high concentrations of hydrogen peroxide containing fluoride (F) or calcium (Ca). Material and Methods: Enamel blocks of bovine incisors with standard dimensions were obtained and half of them were submitted to pH-cycling to promote initial enamel caries lesions. Sound and demineralized enamel samples were divided into (n=10): (C) Control (no whitening treatment); (HP) 35% hydrogen peroxide; and two experimental groups: (HPF) 35% HP+0.2% F and (HPC) 35% HP+0.2% Ca. Experimental groups were submitted to two in-office bleaching sessions and agents were applied 3 times for 15 min to each session. The control group was kept in remineralizing solution at 37°C during the bleaching treatment. The surface mineral content of sound and demineralized enamels was determined through Fourier Transform Raman spectroscopy (FT-Raman), Energy dispersive Micro X-ray fluorescence spectroscopy (μ-EDXRF); and the subsurface, through cross-sectional microhardness (CSMH). In addition, polarized light microscopy (PLM) images of enamel subsurface were observed. Results: According to three-way (FT-Raman and μ-EDXRF analyses) or two-way analysis of variance (ANOVA) (CSMH) and Tukey test (α=5%), the calcium or fluoride added to high-concentrated bleaching agents increased phosphate and carbonate concentrations on sound and demineralized enamels (p<0.05). However, HPC and HPF were unable to completely reverse the subsurface mineral loss promoted by bleaching on sound and demineralized enamels. The calcium/ phosphate (Ca/P) ratio of sound enamel decreased after HP treatment (p<0.001). Conclusion: Even though experimental bleaching agents with Ca or F reduced mineral loss for both sound and demineralized enamel surfaces, these agents were unable to reverse the enamel subsurface demineralization.